Transmitters for producing f-m stereo signals are well known in the prior art. These have the disadvantages of poor signal-to-noise ratio at the receiver output (21 db below mono reception), the stereo channels are separated incompletely by the receiver, and a relatively complicated transmitter and receiver are required. The prior art for stereo f-m transmission is given by L. J. Giacoletto in "The Electronic Designer's Handbook," New York 1977, pages 25-53 to 23-57 inclusive.